INTERESTING article on T5 Reflectors with Diagrams

Discussion in 'Equipment' started by 177ike, Feb 22, 2010.

  1. 177ike

    177ike Guest

    Check out this article:

    http://www.lightingassociates.org/i/u/2127806/f/tech_sheets/FAQs_Reflector_Design__Why_is_it_important_.pdf

    What do you guys think?

    Mike
     
  2. sfsuphysics

    sfsuphysics Supporting Member

    Yeah its no state secret, parabolic reflectors help focus more light where you want it, in the tank.
     
  3. 177ike

    177ike Guest

    I'm just hoping I can get similar growth rates with my T5s as with MH lights.

    I've also noticed the Tek fixtures do not have the 3.75 inch bulb separation, at least the ones made for the aquarium industry. Actually, no aquarium fixtures are designed this way where the peaks extend beyond the bottom edge of the tubes.
     
  4. sfsuphysics

    sfsuphysics Supporting Member

    Ah I see what you were looking at. Well to be honest it depends upon the reflector, my icecap reflectors have bulbs that are very slightly beyond the bottom, and I have some other reflectors (not sure of brand) that extend well beyond the bottom of the bulbs. IMO that company is just doing marketing with that, is there a difference? perhaps a bit, although I'd be willing to bet that 4 bend they do negates most of that benefit vs a more true parabolic shape.

    As to whether you'll get similar growth rates with T5s? Possibly. T5s shine light in a completely different area with a bit less of a hot spot, so if you corals that like that "hot spot" then they won't grow as well. There are many people who have successfully grown corals under T5s however.
     
  5. 177ike

    177ike Guest

    Also this being known, why do so many opt for mh over T5 with the added power consumption? Stricktly for the look alone?
     
  6. Gomer

    Gomer Honorary Member

    specral output is different and they cause different color rendition.
    They have shimmer
    they have more and dynamic shadowing
    their penetration is different (the rate at which light intensity decreases with depth)

    These factors (and a few others) sway people to one or the other.
     
  7. sfsuphysics

    sfsuphysics Supporting Member

    Be careful while *A* T5 bulb might have less power than a MH bulb, MH bulbs can hold their own vs T5s as far as efficiency.

    Here's an AA article that has a particular MH bulb, as well as a T5 fixture and a couple of the LED fixtures out there
    http://www.advancedaquarist.com/2010/2/aafeature2

    In particular 1 250w MH bulb (~300W output) [images are a little too big to post]
    http://www.advancedaquarist.com/2010/2/aafeature2_album/figure_1_lumen_max_ushio_250w_14k_de.jpg

    vs a 6x39W ATi T5 setup, ~250W output
    http://www.advancedaquarist.com/2010/2/aafeature2_album/figure_2_ati_t5.jpg

    It might be hard to tell by the charts, but the T5s peak at about 200, where as the MH are almost 300, that's 50% more light peak light for 20% more power. Plus they both have fairly similar coverages (i.e. the halide isn't all at one small spot. It should also be worth noting that this is a 14000K MH vs 6500K t5s, so the T5s should have that as an added advantage as well.
     
  8. 177ike

    177ike Guest

    I'm not failiar with ATI T5 fixtures. Do they use the reflector design and bulb spread in the article I posted above? The bulb spread needs to be around 3.75 inches apart in order for proper bulb wall cooling according to the article. Since they are testing with a six bulb configuration I'm assuming they are not using a 3.75 inch spread. They are getting similar wattage comparisons to halide tho, albeit with less efficiency of light directed into tank. I certainly noticed the reduced brightness of my PC bulbs when I stuffed my biocube full of PC lighting. I can only fit 4 x 54 watts of T5 over my 90 AGA with the "proper" bulb spread of 3.75 inches. Fixtures such as Tek allow for six bulbs, but the reflectors and bulb separation are not optimal. It seems the majority of people using T5 are not using the above mentioned T5 reflectors due to the availability of the "proper" reflector design in "aquarium T5 fixtures". Just my opinion.
     
  9. Gomer

    Gomer Honorary Member

    Sorry, but I'm not buying the 3.75" as the magic number. Different reflector geometries have trade offs. Optimal is highly relative.
     
  10. 177ike

    177ike Guest

    Agreed, I'm no parabolic reflector or T5 lighting engineer/expert.
     

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